Editing Sarah Blaffer Hrdy (section)

===''The Langurs of Abu''===
Sarah Hrdy first heard of [[langur]]s during an undergraduate [[primate]] behavior class taught by anthropologist [[Irven DeVore]] in 1968. DeVore commented on the relationship between crowding and the killing of infants in langur colonies. After graduation, Hrdy returned to Harvard for graduate studies, with the goal of better understanding the phenomenon of infanticide in primates.<ref name="Sridhar"/> Working under the supervision of DeVore, Trivers and Wilson provided Hrdy with an introduction to the emerging science of [[sociobiology]]—which crystallized at Harvard in the early 1970s.  Sociobiology's comparative evolutionary perspective would shape Hrdy's work for years to come.<ref name="Sridhar"/><ref name="Rees"/>

Although Hrdy had initially gone to [[Mount Abu]] to explore the hypothesis that crowding was responsible for infanticide, soon she realized her starting hypothesis was wrong.  Infants were only attacked when males entered the breeding system from outside it.  This led her to what she termed the sexual selection hypothesis for explaining [[infanticide (zoology)|infanticide]].  Males are eliminating unweaned infants sired by rival males and in doing so inducing the mother to resume cycling and ovulate again sooner than had she continued to lactate. Turnover in her langur troupes occurred roughly on average every 27 months leaving the usurping male only a brief window of opportunity to breed and pass on his genes. If the females are nursing infants, it is likely that they will not [[ovulation|ovulate]] for another year. Killing their dependent infants rendered females fertile again sooner than they otherwise would be.<ref name="Sridhar"/><ref name="Cepelewicz">{{cite news |last1=Cepelewicz |first1=Jordana |title=Why Primates Kill Their Offspring |url=http://nautil.us/blog/human-infanticide-signals-a-lack-of-social-support |access-date=February 11, 2019 |work=Nautilus |date=November 1, 2016}}</ref><ref name="Infanticide">{{cite journal |last1=Hrdy |first1=Sarah Blaffer |title=Infanticide as a Primate Reproductive Strategy: Conflict is basic to all creatures that reproduce sexually, because the genotypes, and hence self-interests, of consorts are necessarily nonidentical. Infanticide among langurs illustrates an extreme form of this conflict |journal=American Scientist |date=1977 |volume=65 |issue=1 |pages=40–49 |jstor=27847641 }}</ref>

Female choice is subverted, as females are put under pressure to ovulate and are forced to breed with the infanticidal males. This is where the idea of [[sexual conflict|sexual counter-strategies]] comes into play. Hrdy hypothesized that by mating with a male who might take over her troupe ahead of time, they protect their infants subsequently born since males were unlikely to kill an infant if there was a chance that it might be their own, a behavior that would be rapidly selected against.<ref name="Dowling"/><ref name="Infanticide"/>

While infanticide by males has since been reported across the primate order in [[Prosimian|prosimians]], New and Old World monkeys, and ape, Hrdy found no evidence to suggest a '[[Genetics|genetic]] imperative' for infanticide in humans.<ref name="langurs">{{cite book |last1=Hrdy |first1=Sarah Blaffer |title=The langurs of Abu : female and male strategies of reproduction |date=1980 |publisher=Harvard University Press |location=Cambridge, MA |isbn=978-0-674-51058-6 |page=290 |url=https://books.google.com/books?id=NYVRhH7VywkC&pg=PA290 |access-date=February 11, 2019}}</ref><ref name="Dowling"/><ref name="Infanticide"/>

In 1975, Hrdy was awarded her PhD for her research on langurs. In 1977 it was published in her second book, ''The Langurs of Abu: Female and Male Strategies of Reproduction''.<ref name="Sridhar"/><ref name="langurs"/> However her proposal that infanticide might be an evolved reproductive strategy in primates proved highly controversial, running counter to the then current conviction that primates act for the good of the group rather than to promote the reproductive interests of any individual.<ref name="Rees"/><ref name="Bekoff">{{cite news |last1=Bekoff |first1=Marc |title=The Strange Relationship Between Virtue and Violence An interview with Richard Wrangham about his new book "The Goodness Paradox" |url=https://www.psychologytoday.com/us/blog/animal-emotions/201902/the-strange-relationship-between-virtue-and-violence |access-date=February 11, 2019 |work=Psychology Today |date=February 11, 2019}}</ref> Nevertheless, her findings have since been replicated in many animals and her explanations are widely accepted.<ref name="Rees">{{cite book |last1=Rees |first1=Amanda |title=The Infanticide Controversy |date=2009 |publisher=University of Chicago Press |isbn=9780226707112}}</ref> Even Trivers, who once dismissed her ideas about female sexual solicitations of multiple males, admits that her theory regarding female counter strategies to infanticide have "worn well."<ref name="Dowling"/>